FIGURE 2.

TEM findings of unencapsulated nerve endings. A, TEM of a FT specimen showing multiple Remak cells within the collagenous core of the FT. Arrows indicate Schwann cell nuclei, asterisks myelinated nerve structures. B, Magnification of 2 Remak cell axon bundles, each accommodating multiple small-caliber axons. Those nerve endings are bulb-shaped and strictly aligned to the course of the surrounding collagenous fibers. C, Larger magnification of a bulbous Remak cell nerve ending. Multiple axons are embedded within the Remak Schwann cell. Note that at the tip of the nerve bulb, collagen fibers are entering the inner core of the nerve ending (arrows). This seems to connect the surrounding collagen tissue to collagen fibrils within the Remak cell axon bundle possibly transmitting stretch forces of the filum to the axons. FT, filum terminale; TEM, transmission electron microscopy.